Campylotropis xinfeniae (Fabaceae, Papilionoideae), a new species from Yunnan, China, based on morphological and molecular evidence

Abstract Campylotropis xinfeniae, a new species from the dry‐hot valley of the Jinsha River in the Yunnan province, China, is described and illustrated. It is morphologically similar to C. wilsonii and C. brevifolia in having glabrescent old branches, absent stipels, 3‐foliolate leaves, and adaxially puberulent leaflets, while it differs from the latter two in having often paniculate inflorescences, obviously white standard, not incurved sickle keel, larger narrowly oblique legumes, and longer legume beak. The complete chloroplast genome of this new species is 149,073 bp in length and exhibits a typical quadripartite structure. Phylogenetic analyses based on the complete chloroplast genome also supported C. xinfeniae as a new species located at the basal distinct clade of the genus Campylotropis, clearly separated from the remaining members of the genus and its allied genera. A conservation assessment of data deficient (DD) is recommended for the new species without extensive exploring of similar habitats according to the IUCN Categories and Criteria.

Liao & B. Xu and C. luquanensis B. Xu & L.S. Jiang (Jiang & Xu, 2021;Liao & Xu, 2020), distributed in the temperate and tropical zones of Asia.China is the center of distribution of Campylotropis, boasting 32 species recognized, among which 20 species are endemic.Of these, 27 taxa including 12 endemics (with nine species, one subspecies, and two varieties) are found in Yunnan.(Fu, 1987;Huang, Ohashi, & Iowaka, 2010;Iokawa & Ohashi, 2002, 2008;Ohashi, 2005;Ohashi et al., 1981).However, the number of species in this region remains uncertain due to changing taxonomic status (Liao & Xu, 2020) and the continuous discovery of new species (Jiang & Xu, 2021).During the floristic investigation conducted in 2019 in the dry-hot valley of the Three Parallel Rivers region in northwestern Yunnan Province, China, we encountered an unknown specimen belonging to the genus Campylotropis, which is different from any known species (Figure 3).This species may resemble C. brevifolia Ricker (1946, p. 37) and C. wilsonii Schindler (1912, p. 343) as they have glabrescent old branches, absent stipels, 3-foliolate leaves, and adaxially puberulent leaflets, one flower per subtending bract (Huang, Ohashi, & Iowaka, 2010).However, the unknown specimens display smaller flowers with obvious white standard, paniculate inflorescences, and calyx tube longer than lobes, larger narrowly oblique legumes, and longer legume beak, which are distinguishable from the other two species (Table 1).We proposed the species new to science based on morphological characters and molecular phylogeny obtained from the chloroplast genome.This study confirmed and reported the discovery of this new species, Campylotropis xinfeniae B. Xu, X.H. Li & L.S. Jiang.

| Morphological analyses
Specimens from two populations of the new species were collected in Yunnan Province (Deqin County and Shangri-La County).
Morphological traits description and measurements (including the size, shape, color, and hair of the stems, leaves, flowers, and fruits;  et al., 2006).The genomic DNA was fragmented, and library sizes were selected for 350 bp inserts.The paired-end library was constructed and subsequently sequenced on BGI (the Beijing Genomics Institute, in Shenzhen, China) sequencing platform DNBseq-T7.

| Phylogenetic analyses
To reveal the phylogenetic relationships of Campylotropis xinfeniae and its related species, this study included the newly generated sequence of C. xinfeniae and 22 accessions representing 17 Campylotropis species (including three subspecies, one variety, and one forma) in previous molecular phylogenetic analysis and five outgroups from GenBank (Table S1) (Feng et al., 2022;Jin et al., 2019;Le & Joonho, 2022;Oyebanji et al., 2020).The whole chloroplast genome sequences of all samples were aligned using MAFFT v7.508 (Katoh & Standley, 2013).The phylogenetic analyses were performed using Maximum likelihood (ML) and Bayesian inference (BI) methods based on whole chloroplast genomes.ModelFinder (Kalyaanamoorthy et al., 2017)

| Characteristics of the complete chloroplast genome
The length of the chloroplast complete genome of Campylotropis xinfeniae sample was 149,073 bp (GenBank: OR506464, Figure 1).It possessed a typical quadripartite structure (LSC, SSC, IRa, and IRb).
The characteristics and statistics of this new species chloroplast genome are summarized in Table 2.

| Phenology
Flowering and fruiting from July to October.

| Etymology
The specific epithet honors Professor Xin-Fen Gao, an outstanding botanist based at Chengdu Institute of Biology, Chinese Academy of Sciences, for her contributions to the taxonomy of Campylotropis (Gao, 2006;Gao et al., 1992).Its Chinese name, xìn fēn háng zǐ shāo (信芬杭子梢), is also suggested here.

| Distribution and habitat
This species so far was only from the dry-hot valley on the Jinsha River in the Yunnan Province (Figure 5).It was observed to grow rocky slopes in dry-hot valleys at elevations of 2100-2500 m.

| Conservation status
Campylotropis xinfeniae is only known from two counties of Yunnan Province, located in the Jinsha River valley zone of the Hengduan Mountains, where sparse vegetation exists in a dry and warm river valley, with high temperatures and minimal precipitation due to the foehn effect.The new species grows in the gallery or riverbank along the dry-hot valley of the upper reaches of the Jinsha River that we investigated (dominant by Sophora davidii Kom.ex Pavol.), mainly on alkaline brown soil (Chang & Li, 2022;Du et al., 2022;Zhang et al., 2013)
Phylogenetically, the monophyly of the two subtribes within Desmodieae was obtained from the phylogenetic analysis in this study had been previously confirmed in previous research (Jabbour et al., 2018;Jin et al., 2019).Similarly, the subtribe Lespedezinae also included three genera: Campylotropis, Lespedeza, and Kummerowia (Han et al., 2010;Kajita et al., 2001;Nemoto et al., 2010;Stefanović et al., 2009, Figure 2).In this study, the sister relationship between Lespedeza and Kummerowia was consistent with the findings based on molecular markers in phylogenetic studies (Jabbour et al., 2018;Xu et al., 2012).Additionally, the sister relationship between the two genera and Campylotropis in this study was reaffirmed and confirmed (Jin et al., 2019).The phylogenetic analysis indicated that Campylotropis is monophyletic for the groups considered (BS = 100%, PP = 1, Figure 2), which is consistent with the results of relationships unresolved.The genus can also be divided into three lineages (Figure 2).Lineage C contained only one species, C. xinfeniae was a sister to all the remaining species of Campylotropis (lineage A and lineage B).Lineage A was mostly restricted to southwestern China and Southeast Asia, and lineage B contained regional endemic (e.g., C. wilsonii) and widely distributed (e.g., C. macrocarpa) species (Huang, Ohashi, & Iowaka, 2010).The phylogenetic analysis revealed Additionally, it can be differentiated morphologically by often paniculate inflorescences, obviously white standard, not incurved sickle keel, larger narrowly oblique elliptic legumes, and longer legume beak.

4. 2
| Diagnosis This new species Campylotropis xinfeniae is morphologically similar to C. brevifolia and C. wilsonii in having glabrescent old branches, absent stipels, 3-foliolate leaves, and adaxially glabrous or sparse puberulent leaflets, one flower per subtending bract, but it differs from both in having often paniculate inflorescences (vs.racemes F I G U R E 1 Chloroplast genome map of Campylotropis xinfeniae.The arrows indicate the transcription directions of the genes inside and outside of the circle.Genes belonging to different functional groups are color-coded.The dark gray area in the inner circle denotes GC content, the light gray to the AT content of the genome.IR, inverted repeat; LSC, large single copy; SSC, small single copy.

Feng
et al. (2022) based on the whole chloroplast genome.However, there are differences in the intrageneric and interspecific relationships of Campylotropis.For instance, the position of C. bonii is no longer a distinct lineage in this study, and the relatively low support between sister lineages in Feng et al. (2022), left the phylogenetic F I G U R E 5 Distribution map of Campylotropis xinfeniae (red circles).
that C. xinfeniae is a distinct new species within the Campylotropis genus, positioned at the basal clade separate from other members and related genera.(BS = 100%, PP = 1, Figure 2).Campylotropis xinfeniae did not form sister clades with its two morphological relatives, C. brevifolia and C. wilsonii, in the molecular phylogenetic trees (BS = 100%, PP = 1, Figure 2).Although they shared morphological similarities, there were distinct genetic differences between them.

DNA extraction, sequencing, assembly and annotation
Detailed comparison among Campylotropis xinfeniae and its morphologically related species.
TA B L E 1(vouchers Xin-Hui Li linxinhui20190910, deposited in the Herbarium CDBI).The total genomic DNA of C. xinfeniae was extracted using a modified cetyltrimethylammonium bromide (CTAB) method(Allen . It is accompanied by Bauhinia rufescens Lam., Indigofera silvestrii Pamp., Stemona japonica (Blume) Miq., Incarvillea arguta (Royle) Royle, Rosa soulieana Crép., and unidentified species of Gramineae.Due to the absence of further exploration in adjacent similar habitats at present, the assessment is therefore categorized as data deficient (DD) according to the IUCN Red List Categories and Criteria (IUCN Standards and